The invention relates to a rotary seal arrangement, comprising a rotatably mounted machine part, a machine part that forms a bearing for the rotatably mounted machine part, wherein a first of the machine parts forms a seal-accommodating structure and the second of the machine parts has a surface forming a sealing surface, and at least one rotary seal arranged in the seal-accommodating structure. The rotary seal allows to seal off a high-pressure area from a low-pressure area between the machine parts.
Rotary seals of this kind are used, for example, to seal rotary feed-throughs. The high-pressure area is then constituted by a rotary feed-through area between the two machine parts. The rotary seal is also termed a rotary feed-through seal. The rotary feed-through permits fluids, that is, gases or liquids, a sealed transition between a stationary machine part and a rotating machine part. The first machine part having the seal-accommodating structure is usually constituted as the stationary machine part and the second machine part, as a shaft mounted rotatably within it. Such rotary feed-throughs are used, for example, in hydraulic applications or to input hot gas for heating a roller.
Known rotary feed-throughs seals are constituted, for example, as a sliding ring (mechanical seal) wherein the sliding ring usually has a sealing ring made of polytetrafluoroethylene (PTFE).
An example of such a rotary feed-through seal is described in DE 10 2007 062 470 A1. A rotary feed-through seal is designed such that as little fluid as possible, which is under positive pressure, enters the low-pressure area from the rotary feed-through area, that is, it is subject to low leakage. However, the lower the leakage, the greater the friction occurring between the sealing surface of the rotatably mounted machine part and the rotary feed-through seal. The wear of the rotary feed-through seal is correspondingly higher and a relatively large amount of driving energy is expended against that friction force. In particular, when shafts rotate at high speeds and with fluids under high pressure, the life of such known rotary feed-through seals is therefore short.
Moreover, entrained rotation of the rotary seal with the shaft must be avoided. This is frequently achieved by pressing the sealing ring into a holding element that is also ring-shaped and is made, for example, of steel. The holding element is mounted torsionally rigidly in the seal-accommodating structure. However, such a rotary feed-through seal is relatively complicated to manufacture. For torsionally rigid mounting, an anti-rotation element must be provided on the seal-accommodating structure and/or the holding element must be pressed into the seal-accommodating structure. Mounting in a simple slot, functioning as the seal-accommodating structure, is not possible because of the rigidity of the holding element.
The object of the invention is to provide a rotary seal arrangement that avoids the disadvantages of the prior art, wherein, in particular, simple mounting of the rotary seal between the machine parts is possible and entrained rotation of the sealing ring of the rotary seal is reliably avoided.